1. Technical Field
The present invention relates to an in vivo drug concentration distribution measuring device, a variable-wavelength filter used for the same, and an in vivo drug concentration distribution measuring method.
2. Related Art
In medical fields, when a drug is administered to a patient, information on the concentration of the drug within the patient's body needs to be acquired in order to minimize any side effect of the drug and achieve satisfactory therapeutic effects. Traditionally, the most common technique is to collect blood from the patient's vein, measure the blood level and analyze the data, thereby analyzing in vivo pharmacokinetics. However, the blood level needs to be measured, for example, at five to six points of time in order to learn accurate pharmacokinetics. It is practically impossible to measure the blood level so many times in usual clinical practice and the measurement is limited to one to two points of time in view of guaranteeing therapeutic effects and safety. Thus, a method for acquiring in vivo drug concentration distribution by a non-invasive technique is required. Moreover, learning the in vivo drug concentration plays an important role not only in treatment but also in development of pharmaceuticals.
Traditionally, the following methods for leaning the in vivo drug concentration are proposed. JP-A-2007-294214 discloses a drug concentration measuring device having an organic sensor which measures in vivo drug concentration of a drug such as aspirin, and a body temperature sensor which measures body temperature. JP-A-2007-519487 discloses a system for adaptively adjusting drug administration. This system uses a technique of measuring changes with time in physiological actions of the patient when a drug is administered, including blood pressure, heart rate and body temperature, and thereby detecting drug concentration. JP-A-2005-211355, though not a technique of measuring concentration, discloses a lymphatic vessel observing device which casts a laser beam to an observation site after administering a contrast agent to a lymphatic vessel, and then detects near-infrared rays radiated from the contrast agent at the time, thereby percutaneously observing the lymphatic vessel.
However, none of the techniques disclosed in JP-A-2007-294214, JP-A-2007-519487 and JP-A-2005-211355 can meet the above needs.
In the technique disclosed in JP-A-2007-294214, when the organic sensor is used, it is necessary to needle a finger tip or the like by a needling device and thus attach blood to a test paper. That is, the technique disclosed in JP-A-2007-294214 can not measure drug concentration distribution by a non-invasive technique. The technique disclosed in JP-A-2007-519487 is to measure physiological actions of the patient when a drug is administered. Therefore, this technique has problems such as occurrence of individual difference in measurement results, poor reproducibility of measurement results, and the lengthy time required for measurement. The device disclosed in JP-A-2005-211355 can observe lymphatic vessels but cannot measure drug concentration distribution.